Compressor for gaseous materials



April 7, 1959 A. T. PLOEGERT COMPRESSOR FOR GASEOUS MATERIALS 2Sheets-Sheet 1 Filed March 13, 1956 INV TOR.

W eg n v 6 8 m 7 0M 7 6w 2 i C A a L T i w w w H 9 5 I x \A\ 7 E W 5 WWum- 000 W a e i April 7, 1959 Filed March 13, 1956 A. T. PLOEGERT2,880,927

COMPRESSOR FOR GASEOUS MATERIALS 2 Sheets-Sheet 2 COMPRESSOR FOR GASEOUSMATERIALS Anatol T. Ploegert, Buffalo, N.Y., assignor to The WittemannCompany, Inc., Buffalo, N.Y.

Application March 13, 1956, Serial No. 571,198

14 Claims. (Cl. 230201) This invention relates to compressors, moreparticularly of the reciprocating displacement type for gases andstroke, and the space between it and the cylinder head was filled withwater, damage to the compressor would result.

It is, consequently, an object of this invention to provide a compressorwhich is so constructed that there is no danger of damage to thecompressor in the event than an excessive amount of water is fed to acylinder.

A further object is to provide a compressor of this type with valveswhich are so located that when opened, water will be discharged throughthe same in advance of compressed gas.

A further object is to provide a two-stage compressor of this type whichincludes only a single reciprocatory piston and in which the cylinderfor the second stage .moves with said piston and cooperates with'astationary piston.

, t It is also an object of this invention to provide a compressor ofthis kind with means of improved construction for cooling the gases inthe compressor.

i Other objects and advantages will be apparent from United StatesPQt-mt "O the following description of one embodiment of the inventionand the novel features will be particularly pointed .out hereinafter inconnection with the appended claims.

In the accompanying drawings:

. Fig. 1 is a longitudinal, central sectional elevation of the upperportion of a compressor embodying this inivention.

a Fig- 2 is a similar view of the lower portion of the compressorshowing the mechanism for imparting reciprocatory-motion to the movablepiston.

The compressor, which is shown in the drawings to illustrate by way ofexample one embodiment of my invention, includes a cylinder 5 in which apiston 6 is reciproca ble in a substantially vertical direction. Thecylinder is provided at the upper end thereof with a cylinder head 7containing one or more valves 8, two being shown in the constructionillustrated. Above the cylinder head 7 is an inlet chamber 9 to whichthe gas to be compressed may be conducted in any suitable man- .ner,.forexample, through an openinglfl formed therein.

.tion, and since valves of this type can be readily purchased ,andare ofmore or less standard construction, they are 'notherein described indetail. They are held in 'place by means of a valve-retaining plate 12vand are inlet valves inlet chamber 9 into the interior of the cylinder 5above the piston 6.

The piston 6 includes the usual head 13 having a sub stantiallygas-tight connection with the inner wall of the cylinder 5, and suitablecompression piston rings 15 and guide or rider rings 15' may be arrangedon the piston head 13 in any usual or suitable manner.

In accordance with my invention, the discharge valves through whichcompressed gas may be discharged from the cylinderare located below thecylinder head so that near the end of the compression stroke the wateror other coolant will be discharged in advance of or simultaneously withthe compressed gas. Consequently, in the con struction shown, I havearranged the discharge valve or valves 14 in piston head, and preferablythese valves are located in depressed portions of the upper surface ofthe piston head, for example, in depressions or re cesses 14 in thepiston head, into which water will flow by gravity during the up strokeof the piston. 1 Conse' quently, when the discharge valves 14 open,water will flow through these valves before gas passes through the same.The piston is reciprocated by means of a piston rod 16 suitably securedat its upper end to the piston head 13.

The piston 6 has a downwardly extending tubular body or skirt portion 18which may, as shown in the drawing, be formed integral with the pistonhead, and for proper guidance of the piston within the cylinder, thisskirt portion is provided at the lower end thereof with an outwardlyextending flange 20 which is also provided with suitable piston rings 21and guide rings 21; to form a substantially gas-tight joint with thelower portion of the cylinder 5.

The downwardly extending, hollow body or skirt portion 18 is bored toform the second stage cylinder of the compressor and cooperates with astationary piston 25 which, in the construction shown, is mounted at theupper end of two concentric cylindrical parts 26 and 28 which are formedintegral at their lower ends with a lower head 27 of the cylinder 5. Thetwo tubular parts 26 and 28 are spaced apart and the cylindrical part 28has an upper portion of increased thickness which supports a series ofpiston rings 30 which cooperate with the cylinder formed by the skirt 18of the upper piston 6. i

The stationary piston head 25 is provided with one or more valves 31,two such valves being shown in the construction illustrated, throughwhich liquid compressed within the second stage cylinder may pass intothe space 32 formed between the two cylindrical piston-supportingmembers 26 and 28, for discharge from the compressor.

In the compressor as so far described, it will be ob.- vious that on thedown stroke of the main piston 6, gas will pass through the valves 8from the inletchamber ,9 into the interior of the cylinder 5. Uponupward movement of the piston 6, this gas is compressed, and uponreaching a predetermined pressure, the compressed gas vwill bedischarged into the second stage cylinder formed second stage cylinderwill consequently be discharged valves 8 may be of; any suitable ordesired constructhrough vwhich. gas tobe compressed.maypassfrom the ,5,

through the valves 31.

When operating with certain gases such, for example, as carbon dioxideproduced in the fermentation process of a brewery, it is, of course,very necessary that the compression of the gas be carried on at a lowtemperature so that certain taste-imparting ingredients or otherconstituents of the gas will not be destroyed or damaged. For thispurpose, water or other coolant which alsoacts as. atlubricant-for.thecontacting surfaces. of .-the cylinder;

pistons is sprayed through the cylinder head 7 by of a suitable :nozzle34 'formed on the end of a water inlet pipe 35 which, in theconstruction shown, extends through the inlet chamber 9 and terminatesin the-suitable nozzle 34. Water may be supplied to this pipe 35 in anysuitable manner (not shown), and is =s'prayed in finely divided forminto the gas which is being compressed. Some of this water will bevaporized, gbut'enough water is injected into the cylinder so that some.of this water also acts as a lubricant for the piston and cylinder. Theexcess water collects on top of the piston head 13, and as soon as thevalves 14 open, this water will be discharged downwardly into the secondistage cylinder formed within the skirt 18, and will thus serve tolubricate the second cylinder and the stationary pistonand also act as acoolant for the gas compressed in the second stage. Similarly, when thepiston 6 is anoved downwardly by the piston rod 16, and when it:approaches closely to the end of the stationary piston 25, water whichhas collected above the valves 31, will be discharged through thesevalves into the space 32 for discharge with the compressed gas to asuitable separator "(not shown), in which the water is removed from thegas.

The base 27 of the cylinder 5 is provided with a gas passage 37 whichconnects with the space 32 and the gas from this passage is dischargedfrom the compressor through an outlet pipe 38.

The main cylinder 5 may be supported on the compressor in any suitableor desired manner, and in the construction shown, this cylinder isprovided with an outwardly extending flange 40 which rests on the upperend of a cylindrical supporting member 41. The piston rod 16 extendsthrough a suitable stuffing boX 42 arranged "in the base 27 and whichmay be of any usual or suitable construction to prevent any lubricantfrom the piston reciprocating mechanism from passing into contact withthe gas being compressed and to prevent Water or other acoolant frompassing down along the rod 16 and contaminating the lubricant used inthe mechanism, which :actuates the piston rod. 43 represents a collarsecured to the piston rod to prevent lubricant from the actuatingmechanism from creeping up along the piston rod.

The discharge pipe 38 extends through a suitable hole or opening 46formed in the supporting member 41. This supporting member in turn issupported by a suitable case or crank case 48 which rests on any desiredfoundation. This base houses mechanism for operating the piston rod 16including a crank shaft 50 journalled in suitable bearings 51 and 52,mounted in opposite walls of the crank case. Rotary motion of the crankshaft 50 is converted into reciprocatory motion in the usual manner bymeans of a crank 54 which imparts motion to one end of a connecting rod55, the other end of the connecting rod being pivotally connected with across head 56 by means of a cross head pin 57. The cross head =56 ismounted as usual, in a suitable cross head slide which may be formed asa part of the crank case 48.

The lower end of the piston rod 16 is rigidly connected "with the crosshead 56. 58 represents an oil pump for lubricating the moving partswithin the crank case and 59 represents a suitable oil seal to resistthe escape of oil from the crank case along the piston rod. Any othermeans for reciprocating the piston may be provided.

In addition to cooling the compressed gas by means of water or othercoolant sprayed into the cylinders, cooling means are also providedabout the cylinder 5 in the form of jackets of any usual orsuitableconstruc- -tin. 63 represents a cylindrical jacket memberextending-about the cylinder and spaced therefrom by outextending ribs64, 65, ,66 which separate the space surrounding the cylinder into anumber of gdifierentcompartments. All but the lowermost of thecompartments formed by these ribs are employed for the simulation of thecoolant. For example, coolant may harnessed into the compartmentxbetweenthe ribs .65and 4 66 through an inlet tube or pipe 68 and passes fromthis compartment through an opening '70 in the cylinder 5 into the spacebetween the piston skirt 18 and the cylinder 5, so that this space isalways filled with coolant, which moves up and down with thereciprocations of the piston. The cylinder 5 is provided with adischarge opening 71 through which liquid from the space surrounding theskirt 18 is discharged into the jacket compartment between the outwardlyextending flanges 64 and 65, and the flange 64 is provided with anopening 72 through which coolant flows into the upper compartment of thejacket from which it is discharged through pipe 73.

It has been ,found that the coolant discharged from the upper jacketcompartment through the pipe 73 is sufficiently cool, so that it may beused for further cooling the gas in the compressor. Consequently, thispipe extends downwardly and terminates in a passage 74 formed in theflange 40 at the lower end of the cylinder 5. This passage leads to anannular passage 75 formed by an annular groove in the lower head 27 ofthe cylinder .5 and facing the flange 40. This passage 75, consequently,extends about the gas passage 37 and thus acts asa jacket to cool gasflowing in the passage 37.

From the passage 75, the coolant flows into a space 76 between thecylinder 5 and the cylindrical portion 28 of the stationary piston. Thisspace also receives any coolant that may leak past either piston and itscylinder and this coolant, together with that discharged from pipe 73,passes through suitable holes or openings '78 leading to the lowestjacket space, and thence to a discharge passage 79 connected with adischarge pipe 80. The holes 78 are preferably spaced slightly above thesurface of the lower head 27 so that a shallow body of coolant will lieon that surface and thus further ab sorb heat from gas in the passage37.

Since the volume of the chamber or space 76 varies with eachreciprocation of the main piston, means are pro vided for preventing anypressure from being generated in this space due to this change in itsvolume, and this is accomplished by means of an equalizing pipe or duct83 which connects with the lowest jacket compartment and with the inletchamber 9, so that gas in the chamber 76 during the down stroke of thepiston will pass through the passages 78 into the lowest jacket chamberand then to the pipe 83 into the inlet chamber 9. During the stroke ofthe piston in the reverse or upward direction, the flow in theequalizing pipe 83 is reversed so that gas is received from the inletchamber 9 and transmitted into the lowest jacket space. Thisconstruction has the advantage that a relatively even flow of gas to becompressed Will enter the inlet chamber 9, since during the downwardstroke of the main piston when gas is drawn from the inlet chamber 9into the cylinder 5, some gas is also discharged from the chamber 76into the-inlet chamber 9. To compensate to some extent for that which isdrawn into the cylinder 5, and during the reverse stroke when no gas istaken into the cylinder 5, a considerable quantity of gas will be drawninto the chamber 76.

By means of the construction described, it will be obvious that damageto the compressor because of excess water or other coolant beingadmitted into a cylinder is entirely eliminated, since if excess wateris passed into a cylinder, it will pass through the discharge valve orvalves in advance of the gas which is being compressed and this isequallytrue in both stages of compression. It is, consequently, possibleby means of the construction shown to admit more coolant to thecylinders than has heretofore been considered practical, andconsequently, more efficient cooling of the gases is efiected, as wellas thoroughly tefiicient lubrication of the bearing surfaces between the'cylindersyand pistons, so that a cooler for the gases be'- tween thetwo stages of compression is not necessary. The maintaining of arelatively large body of water in the space between the piston head andthe lower pistonflange 20 ensures .adequatelubrication of the mainpiston and its cylinder and also ensures efficient cooling of the secondstage cylinder 18.

herein described and illustrated in order to explain the nature of theinvention, may be made by those skilled in the art within the principleand scope of the invention, as expressed in the appended claims.

I claim as my invention:

1. A compressor including an upright cylinder having a cylinder head atthe upper end thereof, a valve in said cylinder head for admitting gasinto said cylinder, a piston reciprocable in said cylinder forcompressing gas between said piston and said cylinder head, said pistonhaving a second cylinder fixed thereon on the face thereof opposite tosaid cylinder head, a stationary piston fitting within said secondcylinder, a discharge valve in said reciprocatory piston for discharginggas compressed thereby downwardly into said second cylinder for further,com-

piston for discharge of the compressed gas, and a reciprocable pistonrod secured to said first mentioned piston and extending downwardlylengthwise through said stationary piston.

2. A two-stage compressor including a cylinder having a cylinder head onthe upper end thereof containing a valve for admitting gas into saidcylinder, a piston reciprocable in said cylinder for effecting the firststage of compression between said piston and said cylinder head, asecond stage cylinder fixed to the lower face of said pistoncoaxiallytherewith, a vvalve in said piston through which gas from the firststage of compression is discharged into saidsecond stage cylinder, astationary piston fitted 'withinsaid second stage cylinder andcooperating therewith duringreciprocation of said first mentionedpiston,

a valve in said stationary piston through which gas from the secondstage is discharged, said first mentioned piston being provided with anenclosure surrounding said second stage cylinder, means in said cylinderhead for supplying liquid coolant to said enclosure, and means forimparting reciprocation to said first mentioned piston.

3. A compressor according to claim 2, in which said enclosure is formedby a flange extending outwardly from the lower part of said second stagecylinder into sliding contact with said first mentioned cylinder andspaced from the head of said first mentioned piston.

4. A compressor according to claim 2, in which openings are provided insaid first mentioned cylinder for admitting cooling liquid into anddischarging the same from said enclosure.

5. A two-stage compressor including a cylinder having a cylinder headcontaining a valve for admitting gas into said cylinder, a pistonreciprocable in said cylinder for effecting the first stage ofcompression between said piston and said cylinder head, said pistonincluding a head and a flange which cooperate with said cylinder andwhich are spaced apart and connected by a second stage cylinder ofsmaller diameter than said head and flange, to form an enclosure forcoolant between said first mentioned cylinder and said second stagecylinder, a valve in said piston through which gas from the first stageof compression is discharged into said second stage cylinder, astationary piston which said second stage cylinder is fitting and whichcooperates during reciprocation of said first mentioned piston, a valvein said stationary piston through which gas from the second stage isdischarged, means in said cylinder head for supplying coolant to saidenclosure, and means for reciprocating said first mentioned piston.

6. A two-stage compressor including a first stage cylinder havingannular spaced ribs extending outwardly therefrom, a jacket memberextending about said cylinder and engaging said ribs and formingtherewith a water jacket divided by said ribs into a plurality ofcompart ments, a piston for reciprocation in said cylinder and having ahead engaging with said cylinder, a second stage cylinder 'formedintegral withsaid piston and extending downwardly. therefrom, anoutwardly extending 'flange on said second stage cylinder, spaced fromsaid cylinder head, said head, flange and said second stage cylinderforming between them an annular space, said first stage cylinder havingan opening communicating with one of said compartments of said jacketfor admitting coolant to the space in said piston and having anotheropening communicating with another compartment for discharging coolantfrom said space, a stationary piston fitted within said second stagecylinder, and means for reciprocating said first mentioned piston.

7. A two-stage compressor including a first stage cylinder having apiston arranged therein, said piston comprising a head at the upper endthereof and a flange at'tlie lower end thereof, said head and flangebeing connected by a cylindrical skirt which forms the cylinder for thesecondstage and which is of smaller diameter than said head and flange,means for admitting coolant into'a'nd discharging coolant from the spacebetween said head and said flange and said first and second stagecylinders from.

8. A two-stage compressor including a first stage cylinder, 'an inletchamber arranged above said cylinder, a piston in said cylinder, saidpiston having a downwardly extending skirt portion forming a cylinderfor the second stage, a stationary piston fitted within said secondstage cylinder, said first mentioned piston having a head at the upperend thereof cooperating with said first mentioned cylinder and La flangeat the lower end of said skirt spaced from said head and also having asliding engagement with said first mentioned cylinder, said stationarypiston being supported on a head secured on the lower end of saidcylinder, the space between said lower head and said flange of saidpiston being variable in volume during the reciprocation of said firstmentioned piston, a tube connecting said space with said inlet chamber,valves on said compressor controlling the flow of gas through saidcompressor, the space above said flange at the lower end of said skirtforming the space for coolant, jackets for coolant extending about saidfirst stage cylinder, and openings in said first stage cylinder forconducting coolant from said jacket into said space and for discharge ofcoolant from said space into said jacket.

9. A compressor including a cylinder having a cylinder head, a pistonreciprocable in said cylinder and having an enlarged head, a secondstagecylinder formed integral with said piston and reciprocable therewith, astationary piston fitted within said second stage cylinder, and meansfor passing coolant about the exterior of said second stage cylinderincluding a flange at the lower end of said second stage cylinder whichextends into sliding engagement with said first mentioned cylinder andwhich forms a space within said first mentioned cylinder and about saidsecond stage cylinder between said piston head and said flange, and onsaid compressor means for circulating coolant through said space.

10. A compressor including a cylinder, a piston reciprocable in saidcylinder, said piston having a downwardly extending skirt portionforming a second stage cylinder, a stationary piston fitted within saidsecond stage cylinder, a hollow cylindrical member supporting saidstationary piston, and terminating at its lower end in a head, said headclosing the lower end of said first mentioned cylinder, a valve in theupper end of said stationary piston through which compressed gas entersinto the space within said cylindrical member, said lower cylinder headhaving openings therein through which the compressed gas passes fordischarge from the compressor, said lower cylinder head having a grooveformed therein fyhich lies adjacent to said ifirst mentioned cylinderand drums a passage for coolant for absorbing heat .from .the

'mitt-ing gas into said cylinder, a piston reciprocable in said cylinderand having a head, means mounted on said .rcylinderforsupplying acoolant into said cylinder above :said piston, 'a valve in said pistonhead through which coolant and compressed gas pass, and a second stagecylinder on the lower face of said piston into which said coolant andcompressed gas are delivered by said last mentioned valve.

12. vA two-stage compressor including a vertical cylindBr having acylinder head, a valve in said head for adrmitting gas into saidcylinder, a piston reciprocable in said cylinder, means mounted on 'saidcylinder for supplying a coolant into said cylinder above said piston, avalve in saidpiston through which coolant and compressed gas gpass, asecond stage cylinder fixed to the lower face of said piston and intowhich gas and coolant pass downwardly from said valve in said piston, astationary piston fitted within said second stage cylinder, a valve inthe upperend of said stationary piston through which gas and coolant aredischarged downwardly, and means for imparting reciprocatory motion tosaid first mentioned piston.

13, A compressor including an upright cylinder having a cylinder head atthe upper end thereof, a valve in said cylinder head for admitting gasinto said cylinder, a

piston.reciprocable in said cylinder for compressing gas between saidpiston and said cylinder head, said piston having a second cylinderfixed thereon on the face thereof opposite .to said cylinder head, astationary piston fitting masons? reciprocatory piston for discharginggas compressed thereby downwardly into said second cylinder for furthercom-- .pression, a discharge valve mounted "on said stationary pistonfor discharge of the gas, and means for supplying "a coolingandlubricating liquidfto the gas in said first mentioned cylinder, which isdischarged through said discharge valve into said second cylinder inadvance of the gas compressed in said first mentioned cylinder.

14. A compressor including an upright cylinder having a cylinder head atthe upper end thereof, a valve in said second cylinder fixed thereon onthe face thereof opposite to said cylinder head, a stationary pistonfitting within said second cylinder, a discharge valve in saidreciprocatory piston for discharging gas compressed thereby downwardlyinto said second cylinder for further compression, a discharge valvemounted on said stationary piston for discharge of the gas, saidcylinders and pistons being arranged on a substantially vertical axiswith said cylinder head uppermost, and means for discharging 'a coolingliquid into the gas above said first mentioned piston, whereby saidliquid will flow by gravity in advance of the compressed gas throughsaid discharge valves when the same are open.

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